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<DIV><FONT color=#0000ff>Randy<SPAN
class=442262219-16022007>:</SPAN></FONT></DIV>
<DIV><SPAN class=442262219-16022007></SPAN> </DIV>
<DIV><SPAN class=442262219-16022007><FONT face=Arial color=#0000ff size=2>As you
experienced, different from other HVAC equipments, the ground loop heat
exchanger (GLHE) can not be auto-sized by eQUEST. There are couple of reasons
for this. </FONT></SPAN></DIV>
<DIV><SPAN class=442262219-16022007><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=442262219-16022007><FONT face=Arial color=#0000ff size=2>First,
the characteristics of GLHE is quite different from other HVAC equipment (i.e .
chiller and boiler), which can be easily and properly sized using the
peak loads. In fact, due to the huge thermal mass of the ground, the history of
rejecting/absorbing heat to/from ground will significantly affect the
performance of a GLHE. Therefore, to properly size a GLHE, not only the
peak loads but also the loading history have to be accounted for. As a
result, eQUEST can not properly auto-size a GLHE before the annual
simulation is performed. </FONT></SPAN></DIV>
<DIV><SPAN class=442262219-16022007><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=442262219-16022007><FONT face=Arial color=#0000ff
size=2>Second, there are lots of variations in the design of GLHE, such as
borehole field configuration (geometry pattern), borehole depth, grouting
material, borehole spacing, etc. These variations may significantly affect the
required size of GLHE. Since GLHE is a relatively expensive device, it is really
necessary for the designer to try various possible GLHE designs, perform
simulations, evaluate the results, and finally achieve the optimal design.
Although technically speaking, it is possible to make eQUEST be able to
auto-size GLHE (which required multiple eQUEST runs controlled by certain
iteration procedure), the auto-sized GLHE is by no means the optimal
design.</FONT></SPAN></DIV>
<DIV><SPAN class=442262219-16022007><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=442262219-16022007><FONT face=Arial color=#0000ff size=2>There
are also couple of notes regarding eQUEST GSHP simulation you may be interested
in:</FONT></SPAN></DIV>
<DIV><SPAN class=442262219-16022007><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=442262219-16022007><FONT face=Arial color=#0000ff size=2>1.
Warning messages will be given in the detailed simulation output file (XX.sim)
if GSHP Water Loop temperature has exceeded a hi/low alarm. For example,
following is the warning message shown in your output file. This warning message
has to be taken care of since the heat pump unit will be shut down when the loop
temperature exceeds the hi/low alarm. It is true in both the reality
and the simulation. As a result, the room temperature could not be maintained at
the thermostat set point. If this happen, you will see (in BEPS or SS-R
report) high percentage of hours that the room temperature is outside of
the throttling range. In this case, you need adjust the design of your GLHE
incrementally until this message disappear. </FONT></SPAN></DIV>
<DIV><SPAN class=442262219-16022007></SPAN> </DIV>
<DIV><SPAN class=442262219-16022007></SPAN><SPAN class=442262219-16022007><FONT
face="Courier New"
size=1>**WARNING**********************************************************************</DIV>
<DIV>
<P>WLHP loop: GSHP Water Loop has exceeded a hi/low</P>
<P>alarm limit and will shut down associated HVAC equipment</P>
<P>for the hour. Loop T: 110.26 Limit: 110.00</P>
<P>Verify that alarm limits are reasonable, verify primary</P>
<P>equipment sizing, especially ground-loop heat-exchangers,</P>
<P>and verify that the HP performance curves are suitable for</P>
<P>the intended operating range. See Report PS-D for total</P>
<P>number of hours alarm limits are exceeded.</P>
<P>First occurrence: 7/19/17</P>
<P><FONT face=Arial size=2><FONT color=#0000ff>Actually, the better way to
wat<SPAN class=442262219-16022007>ch</SPAN> the performance of a GLHE is
to <SPAN class=442262219-16022007>let eQUEST </SPAN>output the hourly
report of the GLHE outlet temperature, which is the entering fluid temperature
to the heat pump if the thermal loss from the loop and the pump temperature rise
can be ignored. <SPAN class=442262219-16022007>As an example, to output the
hourly loads on GLHE, outlet temperature of GLHE, and the undisturbed ground
temperature, you can save following text as a short inp file and add it to your
input file by using the "Import files" feature of eQUEST in the detailed
mode. For advanced users, you can directly define the hourly report in the
detailed mode of eQUEST.</SPAN></FONT></P></FONT>
<P><FONT face=Arial color=#0000ff size=2>$
---------------------------------------------------------<BR>$
Hourly Reporting<BR>$
---------------------------------------------------------</FONT></P>
<P><FONT face=Arial color=#0000ff size=2>"GHX" = REPORT-BLOCK
<BR> VARIABLE-TYPE = "GLHX
(VertWell-CM)"<BR> VARIABLE-LIST = ( 1, 4, 5
)<BR> ..<BR></FONT><FONT face=Arial color=#0000ff size=2>"Hourly
Report" = HOURLY-REPORT <BR> LIBRARY-ENTRY "Hourly
Report"<BR> ..<BR>"Hourly Report 3" = HOURLY-REPORT
<BR> REPORT-SCHEDULE = "Hourly Report
Schedule"<BR> REPORT-BLOCK = ( "GHX"
)<BR> ..</FONT></P>
<P><FONT face=Arial color=#0000ff size=2><SPAN class=442262219-16022007>2.
Mutli-year performance of GLHE has to be considered when you size GLHE,
especially when large borehole field is used and the heat rejected to the ground
can not be balanced by heat absorbed from the ground on an annual basis. In this
case, although the GLHE loop temperature is within the limit at the first year,
it may be outside of the limit just couple of years later. To observe the
performance of a GLHE after multi-year operation, you can change the input
"Years of previous operation" from the default 0 to other positive integers, and
run the simulation again.</SPAN></FONT></P>
<P><FONT face=Arial color=#0000ff size=2><SPAN class=442262219-16022007>3. The
"Number of identical borehole field" is only an approximate approach to describe
and simulate large borehole fields. DOE-2 assumes that the identical well fields
do not interact with each other. This assumption is only valid when the
identical well fields are apart from each other with enough distance. For large
vertical well field with many boreholes placed closely, it is recommended to use
the exact borehole field configuration in the simulation. Data for
simulating more borehole field configurations than the 41 existing
configurations are available upon request.</P></SPAN></FONT>
<P><FONT face=Arial color=#0000ff size=2><SPAN class=442262219-16022007>4. New
reports for GLHE will be added to eQUEST in near future. Hopefully, it will make
the the iterative GLHE design procedure described above a little bit
easier.</SPAN></FONT></P>
<P><FONT face=Arial color=#0000ff size=2><SPAN class=442262219-16022007>Hope it
helps,</SPAN></FONT></P>
<P><FONT face=Arial color=#0000ff size=2><SPAN class=442262219-16022007>Xiaobing
Liu</SPAN></FONT></P>
<P><FONT face=Arial color=#0000ff size=2><SPAN
class=442262219-16022007></SPAN></FONT> </P></FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> BLDG-SIM@gard.com
[mailto:BLDG-SIM@gard.com]<B>On Behalf Of </B>Randy Wilkinson<BR><B>Sent:</B>
Wednesday, February 14, 2007 6:59 PM<BR><B>To:</B>
BLDG-SIM@gard.com<BR><B>Subject:</B> [BLDG-SIM] Mysterious space heating load
spikes - RESOLVED<BR><BR></FONT></DIV>Thanks to all,<BR><BR>Brody and at least
one other suggested using a larger GSHP ground loop. That fixed
it. Thanks for your help.<BR><BR>Randy<BR><BR>Brody Wilson wrote:
<BLOCKQUOTE cite=midMDAEMON-F200702131545.AA4527718pd80002523941@gard.com
type="cite">Randal,<BR> I just ran into this issue myself, it
looks like the temperature alarms on your GSHP Water loop are alarming and
shutting off your equipment, then the loop returns to non alarm temps, then
the equipment cycles back on, etc. <BR>It looks like you're alarming on both
the high and low sides, so I'm guessing that whatever heat source or heat
sink you have are too small. If you have a ground source heat exchanger make
it bigger and see if that fixes it. <BR><BR>Let me know if that's it.<BR><PRE class=moz-signature cols="72">--
Brody Wilson
Phone: 314.644.2629
Fax: 314.644.0691
Mobil: 314.651.8319
Energy Solutions Inc.
P.O. Box 300354
St. Louis, MO 63130
<A href="mailto:brody@energysolutions-stl.com">brody@energysolutions-stl.com</A>
<A href="http://www.energysolutions-stl.com">www.energysolutions-stl.com</A></PRE><BR><BR><BR><BR>
<DIV><SPAN class=gmail_quote>On 2/9/07, <B class=gmail_sendername>Randy
Wilkinson</B> <<A
href="mailto:randy@hvacware.net">randy@hvacware.net</A>> wrote:</SPAN>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">
<DIV text="#000000" bgcolor="#ffffff">Hi All,<BR><BR>Our eQuest model has
<A onclick="return top.js.OpenExtLink(window,event,this)"
href="http://www.lseng.com/%7Erandyw/stegasaurus.pdf" target=_blank>very
strange looking spikes</A> in the space heating load profile. We
can't figure out why they would be there. I put a PDF of the Monthly
Electric Peak Load Profile on <A
onclick="return top.js.OpenExtLink(window,event,this)"
href="http://www.lseng.com/%7Erandyw/" target=_blank>my web
page</A>. The is also a PDF of the <A
onclick="return top.js.OpenExtLink(window,event,this)"
href="http://www.lseng.com/%7Erandyw/simulationoutput.pdf"
target=_blank>complete simulation output</A> if that helps. We did a
sanity check of inputs...it still looks insane. This model was done
all with DD wizard inputs. Anybody got any ideas? TIA.<BR><BR><A
onclick="return top.js.OpenExtLink(window,event,this)"
href="http://www.lseng.com/%7Erandyw/"
target=_blank>http://www.lseng.com/~randyw/</A><BR><A
onclick="return top.js.OpenExtLink(window,event,this)"
href="http://www.lseng.com/%7Erandyw/stegasaurus.pdf"
target=_blank>http://www.lseng.com/~randyw/stegasaurus.pdf</A><BR><A
onclick="return top.js.OpenExtLink(window,event,this)"
href="http://www.lseng.com/%7Erandyw/simulationoutput.pdf"
target=_blank>http://www.lseng.com/~randyw/simulationoutput.pdf</A><BR><BR>Randy<BR>
<DIV>-- <BR><SPAN
style="FONT-WEIGHT: bold; FONT-SIZE: 11pt; COLOR: black; FONT-FAMILY: Arial">Randall
C. Wilkinson </SPAN><SPAN
style="FONT-WEIGHT: normal; FONT-SIZE: 8pt; COLOR: rgb(102,102,102); FONT-FAMILY: Arial"></SPAN><BR><SPAN
style="FONT-WEIGHT: normal; FONT-SIZE: 8pt; COLOR: rgb(102,102,102); FONT-FAMILY: Arial"></SPAN><SPAN
style="FONT-WEIGHT: normal; FONT-SIZE: 8pt; COLOR: rgb(102,102,102); FONT-FAMILY: Arial">L&S
Engineering<BR>Spokane, WA<BR></SPAN></DIV><PRE>======================================================
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